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1.
Sci Total Environ ; 751: 141659, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32882552

RESUMO

Addition of carbon-based byproducts in urban soil is gaining popularity as a plant growth stimulator, soil quality enhancer and fostering green land vegetation. A 60-day trial experiment was carried out for investigating the impacts of sugarcane, neem and bamboo mixed biochar and polyvinyl chloride (PVC), polyethylene (PE) and polyethylene terephthalate (PET) mixed plastic char (1:100, 2:100 and 4:100 char: soil ratio) on physico-chemical properties of soil and growth of Dendrocalamus strictus saplings. It was found that available phosphorus increased from 412.16 to 586.88 kg h-1 which could be attributed to reduced metal ion activity due to increase in the soil pH (7.75-7.81) and CEC (98.07-131.04 mEq 100 g-1). The application of both the char enhanced the quality of soil and thereby helped in achieving higher crop yields. Both biochar and plastic char increased the soil pH, total organic carbon, available phosphorus and nitrogen in the soil. Additionally, the results showed an entirely positive influence of the chars on plant height thereby making it more suitable for the improvement of agricultural system and reducing the dependency on market-based fertilizers.


Assuntos
Carbono , Solo , Carvão Vegetal , Fertilizantes/análise , Nitrogênio/análise , Fósforo
2.
Sci Total Environ ; 750: 141699, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182212

RESUMO

In the attempt to close nutrient cycles, organic fertilizers and soil improvers are getting interest as renewable P sources for crops. However, both the P availability of these compounds for crops and the underlying mechanisms are not fully understood. In this study composts (n = 8), biochars (n = 5), animal manure and processed animal manure (n = 13), digestates and processed digestates (n = 15) and blends of digestates with compost/animal manure/mineral fertilizers (n = 15) were analyzed for chemical composition, organic matter stability and P use efficiency (PUE). Biodegradability (=holocellulose/lignin ratio) proved to be a good indicator for organic matter stability and can successfully replace time-consuming incubation experiments in standard analyses of organic fertilizers. The PUE of digestates, struvites, animal manure products and blends of digestate with compost/animal manure/mineral fertilizers was determined by the NH4+-N, Mg and Fe content of the organic fertilizers. The PUE can be predicted by PUE = 61.34 + 8.59*NH4+-N/P + 42.25*Mg/P - 8.09*Fe/P (R2 = 0.71). As increasing amounts of NH4+-N and Mg stimulate the formation of soluble struvite crystals, increasing PUE is explained by an increasing amount of P as struvite. The PUE of biochars and composts was determined by the Ca/P and Al content of the organic fertilizers. Here, PUE can be predicted by PUE = 88.87-1.07*Ca/P + 6.08*Al/P (R2 = 0.93). As increasing amounts of Ca stimulate the formation of highly stable apatite crystals, increasing PUE is explained by an increasing amount of P in the form of apatite.


Assuntos
Compostagem , Esterco , Animais , Carvão Vegetal , Fertilizantes/análise , Nitrogênio/análise , Solo , Estruvita
3.
Sci Total Environ ; 752: 141885, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32890835

RESUMO

In agriculture, the applied nitrogen (N) can be lost in the environment in different forms because of microbial transformations. It is of special concern the nitrate (NO3-) leaching and the nitrous oxide (N2O) emissions, due to their negative environmental impacts. Nitrification inhibitors (NIs) based on dimethylpyrazole (DMP) are applied worldwide in order to reduce N losses. These compounds delay ammonium (NH4+) oxidation by inhibiting ammonia-oxidizing bacteria (AOB) growth. However, their mechanism of action has not been demonstrated, which represent an important lack of knowledge to use them correctly. In this work, through chemical and biological analysis, we unveil the mechanism of action of the commonly applied 3,4-dimethyl-1H-pyrazole dihydrogen phosphate (DMPP) and the new DMP-based NI, 2-(3,4-dimethyl-1H-pyrazol-1-yl)-succinic acid (DMPSA). Our results show that DMP and DMPSA form complexes with copper (Cu2+) cations, an indispensable cofactor in the nitrification pathway. Three coordination compounds namely [Cu(DMP)4Cl2] (CuDMP1), [Cu(DMP)4SO4]n (CuDMP2) and [Cu(DMPSA)2]·H2O (CuDMPSA) have been synthesized and chemical and structurally characterized. The CuDMPSA complex is more stable than those containing DMP ligands; however, both NIs show the same nitrification inhibition efficiency in soils with different Cu contents, suggesting that the active specie in both cases is DMP. Our soil experiment reveals that the usual application dose is enough to inhibit nitrification within the range of Cu and Zn contents present in agricultural soils, although their effects vary depending on the content of these elements. As a result of AOB inhibition by these NIs, N2O-reducing bacteria seem to be beneficed in Cu-limited soils due to a reduction in the competence. This opens up the possibility to induce N2O reduction to N2 through Cu fertilization. On the other hand, when fertilizing with micronutrients such as Cu and Zn, the use of NIs could be beneficial to counteract the increase of nitrification derived from their application.


Assuntos
Nitrificação , Óxido Nitroso , Agricultura , Fertilizantes/análise , Óxido Nitroso/análise , Solo , Microbiologia do Solo
4.
Sci Total Environ ; 752: 141795, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32892043

RESUMO

Sugarcane is the second largest bioenergy crop in the world and it accounts for 80% of global sugar production. Grown mostly in wet and warm tropics with relatively high nitrogen (N) fertiliser input and crop residue retention, sugarcane production is a significant source of nitrous oxide (N2O) emission. Yet, a global evaluation of research on N2O emission from sugarcane crop is lacking. Here, we conducted a meta-analysis using data from 141 measurements compiled from 15 sugarcane field studies reported from different countries to i) quantify N2O emissions and emission factors (EFs) globally, and for tropics and sub-tropics, and ii) identify the key factors that promote N2O emission. Our analysis shows that the global mean total N2O emission from sugarcane production reached 2.26 (CI: 1.93-2.62) kg N2O-N ha-1 yr-1 with an estimated EF of 1.21% (CI: 0.971-1.46%). N2O emissions increased exponentially with increase in N fertiliser rate, questioning the adequacy of Intergovernmental Panel on Climate Change (IPCC) default EF value (1%) for sugarcane N2O emission estimation. Mean total N2O emissions and EFs in tropics and sub-tropics did not vary significantly. Supplementing synthetic N fertiliser (SN) with organic amendments (OA) significantly increased mean N2O emission (~1.4-fold) and EF (~2.5-fold) compared to SN. A remarkable reduction in N2O emission (38.6%) and EF (61.5%) was evident when enhanced efficiency fertilisers (EEF) replaced SN. In contrast, crop residue removal had little impact on N2O emission and EF, but both parameters showed an upward trend with irrigation and increased rainfall. Soil carbon content and pH were emerged as key regulators of sugarcane N2O emission and EF. It is concluded that global sugarcane N2O emission could be significant and that there is considerable prospect for mitigating the emission through innovative nutrient formulations and precision agriculture that help meet crop nutrient demand without compromising environmental imperatives.


Assuntos
Óxido Nitroso , Saccharum , Agricultura , Fertilizantes/análise , Nitrogênio , Óxido Nitroso/análise , Solo
5.
Sci Total Environ ; 753: 141984, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32906047

RESUMO

Sediment removal from eutrophicated shallow lakes may not only be an effective method for lake restoration but also provides the potential for recycling nutrients from sediments to crop production. However, finding a suitable strategy for sustainably reusing the sediment remains a challenge. Therefore, current study focused on the best practices in applying the sediment from a shallow eutrophicated lake to the soil in terms of grass yield, nutrient uptake, and nutrient leaching. During a nine-month lysimeter experiment, 100-cm high columns were filled with six combinations of soil, sediment, and biochar, with or without meat bone meal organic fertilizer. Aboveground biomass, root mass distribution in soil, nutrient concentration, phosphorus (P) uptake of perennial ryegrass (Lolium perenne L.) along with easily soluble nutrients in the growing medium, and leached mineral nitrogen (N) and P levels were measured. Plant growth conditions were improved by sediment additions, as the yield and P uptake of ryegrass nearly doubled in treatments containing sediment compared to the control soil. While the sediment was richer in macro and micronutrients (e.g. P and N) compared to the soil, the leached N and P levels from both treatments were almost equivalent (N < 830 mg m-2 and P < 3 mg m-2). In addition, applying a 2-cm layer of biochar between the sediment and soil reduced P and N leaching by 50%. According to the results, applying a 75-cm thick layer of sediments on agricultural sandy loam soils surrounding the lake seems a promising practice for improving plant yield and soil nutrient status without increasing of P and N leaching from soil.


Assuntos
Agricultura , Lagos , Fertilizantes/análise , Nitrogênio/análise , Nutrientes , Fósforo , Solo
6.
Huan Jing Ke Xue ; 41(11): 5176-5184, 2020 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124262

RESUMO

Ammonia volatilization is one of the major paths of nitrogen (N) loss and may exert a substantial impact on air quality. This study aims to explore the effects of nitrogen (N) fertilizer types, fertilization rate, and application timing and gas collection method on NH3 volatilization during the maize season in Northern China. This study collected the publications on the NH3 volatilization from maize farming which were conducted in Northern China from 1980 to 2018, and undertook a systematic analysis. The study found that with the increase of N rate, the total and net NH3 volatilization at the basal and topdressing fertilization stages increased at exponential and power function, respectively. When the ratio of basal/topdressing N rate was 1/1, the total and net NH3 volatilization during the topdressing stage (58.4% of the whole season emission) was significantly higher than that in the basal fertilization stage (41.6%) (P<0.05). The priming effect first showed a negative effect and then gradually turned into a positive effect with the increase of N rate. Due to the positive priming effect, the net NH3 volatilization, without considering the priming effect, was overestimated under the conventional N application (>297 kg·hm-2). There is a significant difference between the NH3 volatilization measured by the venting method and the sponge absorption method, and the data from the venting method are more stable (P<0.01). Compared with conventional urea, slow-release urea may reduce NH3 volatilization by 20% to 50%. Control fertilizer N rate at the topdressing stage is more efficient in reducing the NH3 volatilization from maize production in Northern China, and the venting method is more suitable for the quantification of NH3 volatilization than the sponge absorption method under a high rate of fertilizer N.


Assuntos
Amônia , Nitrogênio , Agricultura , Amônia/análise , China , Fertilizantes/análise , Nitrogênio/análise , Estações do Ano , Solo , Volatilização , Zea mays
7.
Huan Jing Ke Xue ; 41(9): 4226-4233, 2020 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124304

RESUMO

A field experiment with an orthogonally designed experiment L9(34) was designed to investigate the effect of different N, P, and K levels on plant growth and Cd uptake by Hylotelephium spectabile. The results showed that the biomass of H. spectabile significantly increased with the N application rate. The highest dry weight in the shoot occurred in the treatments with a high level of N (337.5 kg ·hm-2), which was 0.86-2.00 times higher than the value with no fertilizer treatment. The addition of K contributed to promoting the Cd absorption of H. spectabile, while no effect was observed when N and P were added. Consequently, NPK fertilizers contribute to increasing the Cd uptake of H. spectabile, and the N and K fertilizer play important role in plant growth and Cd absorption respectively. Moreover, the effect of fertilizers on Cd uptake of H. spectabile was in the order of N > K > P, which indicated that N fertilizer was the main factor for promoting the Cd phytoextraction efficiency of H. spectabile by increasing the biomass. Therefore, the application of high levels of N combined with moderate levels of P and K will be an effective approach to improve the Cd phytoremediation efficiency of H. spectabile by promoting its growth, and the Cd uptake can be increased by a factor of 0.9-2.2 compared to no fertilizer treatment condition.


Assuntos
Cádmio , Poluentes do Solo , Biodegradação Ambiental , Cádmio/análise , Fertilizantes/análise , Nitrogênio , Nutrientes , Solo , Poluentes do Solo/análise
8.
Huan Jing Ke Xue ; 41(9): 4262-4272, 2020 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124308

RESUMO

To investigate the effect of typical manure application on soil microbes in paddy fields, a field experiment on manure application in Chongming Island was carried out. The composition and variety of soil microorganisms in rice paddy fields were analyzed using high-throughput theory (CK), chicken manure (CM), pig manure (PM), and organic fertilizer (OF). The results showed that compared with CK, the application of organic manure increased soil organic matter (SOM), and the application of chicken manure significantly increased the soil ammonia nitrogen (NH4+-N) and total nitrogen (TN) contents (P<0.05). Soil microbial diversity in the PM group was significantly higher than that in the CK group (P<0.05), and the soil microbial community richness in the OF group was significantly higher than that in the CM group (P<0.05). pH, total phosphorus (TP), total nitrogen, and Pb were the important factors affecting the composition of soil microbial communities in paddy fields. The microbial community structure in the CM group was significantly different from those in the other three groups. Compared with CK, the OF group increased the relative abundance of Nitrospira, and the CM group significantly reduced the relative abundance of the denitrifying bacteria Ignavibacteriae (P<0.01) to 40.56%, but significantly increased the relative abundance of nitrifying bacteria Thauera(P<0.05) to 203.00%. The PM group significantly increased the relative abundance of ammoniated bacteria Armatimonadetes (P<0.05) to 57.51% and the anaerobic strain Anaerolinea to 102.00%. The application of chicken manure and pig manure significantly increased the relative abundance of pathogens Pseudomonas and Flavisolibacter (P<0.05), respectively, while the application of organic manure reduced the relative abundance of Flavisolibacter. Overall, the application of manure increased the abundance of bacteria involved in the nitrogen cycle of paddy soils and played a positive role in regulating the nitrogen balance in paddy soils. However, direct application of chicken manure and fresh pig manure increased the abundance of pathogenic bacteria, which had a certain degree of stress on the soil health in the paddy field.


Assuntos
Microbiota , Oryza , Agricultura , Animais , Fertilizantes/análise , Esterco , Nitrogênio , Solo , Microbiologia do Solo , Suínos
9.
Huan Jing Ke Xue ; 41(8): 3811-3821, 2020 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124358

RESUMO

Combining organic fertilizer with chemical fertilizer may affect the microbial processes related to nitrous oxide (N2O) emissions under different degrees of soil salinization. A mild saline soil (S1; electrical conductivity (EC) 0.46 dS·m-1) and moderate saline soil (S2; EC 1.07 dS·m-1) in the Hetao irrigation district of Inner Mongolia were selected. Under equal N rates, the study involved five treatments:U1 (240 kg·hm-2 of chemical fertilizer), U3O1 (180 kg·hm-2 of chemical fertilizer+60 kg·hm-2 of organic fertilizer), U1O1 (120 kg·hm-2 of chemical fertilizer+120 kg·hm-2 of organic fertilizer), U1O3 (60 kg·hm-2 of chemical fertilizer+180 kg·hm-2 of organic fertilizer), and O1 (240 kg·hm-2 of organic fertilizer). In addition, a blank control treatment (CK) was employed to investigate the effects of different fertilization treatments on the N2O emissions from the two saline soils. The results showed that the total N2O emissions from the S2 soil in the same treatment were between 11.86% and 47.23% higher than those from the S1 soil (P<0.05). the dynamic trend of the soil N2O fluxes among the different treatments were similar. The peak N2O emissions occurred after fertilization, and the N2O cumulative emission fluxes accounted for nearly 60% of the emissions during the entire growth period. The proper application of organic fertilizer could significantly reduce the soil N2O emission; the S1 and S2 saline soils treated with U1O1 and O1, respectively, had the lowest N2O emissions, whereby there were significant reductions of 33.62% and 28.51% in comparison to the U1 treatment (P<0.05). Moreover, higher maize yields could be obtained and the N2O flux was significantly positively correlated with the NH4+-N content (P<0.01) but negatively correlated with the NO3--N content. The results demonstrated that nitrification was the main way to produce N2O in the studied salinized maize farmland, and that the addition of organic fertilizer could reduce the N2O production by decreasing the soil NH4+-N content. Based on the changes in the corn yield and a reduction in the greenhouse effect, suitable organic and inorganic fertilizer management models for the Hetao irrigation area were the mild saline soil:120 kg·hm-2 of urea +120 kg·hm-2 of organic fertilizer), and the moderate saline soil:240 kg·hm-2 of organic fertilizer.


Assuntos
Fertilizantes , Solo , Agricultura , China , Fertilizantes/análise , Nitrogênio , Óxido Nitroso/análise
10.
Huan Jing Ke Xue ; 41(8): 3855-3861, 2020 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124363

RESUMO

A field experiment involving eight treatments with water management combined with leaf spraying silicon fertilizer was conducted in a paddy field heavily contaminated with Cd (2.83 mg·kg-1) to study the effects of these treatments on rice growth and Cd accumulation in different rice tissues. The results showed that:① the treatments had no significant effects on rice plant height or number of tillers, but increased the biomass of brown rice by 1.7% to 25.0%. Among the eight treatments, that of water flooding during the rice maturation period plus leaf spraying silicon fertilizer (CY) resulted in the highest amount of brown rice yield. ② The treatment of conventional water management plus leaf spraying silicon fertilizer (Si) had no significant effect on the exchangeable Cd content and TCLP extractable Cd content in soil, whereas the other treatments reduced the exchangeable Cd content by 7.8%-42.6% and the TCLP extractable Cd content by 20.0%-40.8%. ③ The Si treatment could reduce the Cd content in various rice tissues, with an overall decrease of 19.0% in brown rice. The other treatments significantly reduced the Cd content in various rice tissues. The treatment of moisture during the rice maturation period plus leaf spraying silicon fertilizer (CS) resulted in the highest reduction in the Cd content in brown rice (44.0%), and was followed by the treatments of batch-type water flooding during the entire rice growth period plus leaf spraying silicon fertilizer (JX; 36.4%), and moisture during the rice pustulation period plus leaf spraying silicon fertilizer (GS; 31.8%). ④ For paddy-fields that are contaminated with Cd to medium and heavy levels, the CS and JX treatments are recommended to manage rice production in order to significantly reduce the Cd content of brown rice whilst having little effect on the rice yield.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Fertilizantes/análise , Folhas de Planta/química , Silício , Solo , Poluentes do Solo/análise , Água , Abastecimento de Água
11.
Huan Jing Ke Xue ; 41(10): 4711-4718, 2020 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124404

RESUMO

In this study, we investigated the effectiveness and microbial mechanism of Bacillus amyloliquefaciens biofertilizer on reducing ammonia volatilization in farmland soil. Pot experiments were carried out to explore the effects of B. amyloliquefaciens biofertilizer (BB) and chemical fertilizer on soil ammonia volatilization, crop yield and quality, and soil microbial community. Four fertilization strategies were tested, namely no fertilizer (CK), 100% chemical fertilizer (C), 50% BB and 50% chemical fertilizer (B1), and 100% BB (B2). The dynamic flow-through chamber method was used to determine the soil ammonia volatilization flux after fertilization. The soil bacterial community during the peak period of ammonia volatilization was analyzed using 16S rDNA high-throughput sequencing. The results showed that the amount of ammonia volatilization in B1 and B2 decreased by 79.5% and 84.8%, respectively, as compared with treatment C. B2 had the lowest nitrate content and the highest yield; the yield of B2 increased by 50.5% and 12.3% as compared to that of CK and C, respectively. B1 had the highest content of vitamin C, which was 67.6 mg ·kg-1. The application of BB improved the diversity and richness of soil bacterial community, especially the relative abundance of Bacillus and Nitrospira. This shows that BB plays an important role in preventing air pollution and improving nitrogen utilization.


Assuntos
Bacillus amyloliquefaciens , Solo , Amônia/análise , Fertilizantes/análise , Nitrogênio/análise , Volatilização
12.
Sci Total Environ ; 748: 142457, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113706

RESUMO

As a good soil synergist, biochar has a wide prospect in improving soil fertility and crop production. Although hydrochar, produced by hydrothermal carbonization process has attracted attention due to production advantages, hydrochar application in low fertility soils as well as its impact to the associated greenhouse gas (GHG) emissions in farmlands is rarely reported. To advance our understanding on the effect of hydrochar addition on grain yield from low fertility soils and the corresponding CH4 and N2O emissions, a soil-column experiment, with two hydrochar types (sawdust-derived hydrochar (SDH), microbial-aged hydrochar (A-SDH)) at two application rates (5‰, 15‰; (w/w)), was conducted. The results showed that hydrochar addition evidently increased rice yield. The N2O emissions were mainly related to the substrate supply of the hydrochar itself and less affected by the denitrifiers (functional genes) present. Hydrochar amendment at low application rate (5‰; SDH05, A-SDH05) significantly decreased the cumulative N2O emissions by 26.32% ~ 36.84%. Additionally, hydrochar amendment could not increase the CH4 emissions due to the substrate limitation; the cumulative emissions were similar with those from the control, ranging between 11.1-12.8 g m-2. Regarding grain yield and global warming potential, greenhouse gas intensity from the soils subjected to hydrochar (SDH05, A-SDH05, A-SDH15) were significantly lower than that of the control, observation attributed to the high yield and low N2O emissions. Overall, hydrochar addition is an effective strategy to ensure grain yield in low fertility soils with relatively low/controlled GHG emissions, especially when the amendment is applied at low application rate.


Assuntos
Gases de Efeito Estufa , Oryza , Agricultura , Carvão Vegetal , Ecossistema , Fertilizantes/análise , Metano/análise , Óxido Nitroso/análise , Solo
13.
J Environ Qual ; 49(2): 440-449, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016427

RESUMO

The use of suctions cups is a common practice for estimating nitrate (NO3 -N) leaching under agricultural systems despite the various uncertainties associated with the approach. One major uncertainty is water flux, which is required for calculating NO3 -N leaching loads from measured concentrations. Another problem is the interpolation of NO3 -N concentrations between measurement days. We investigated how differences in water flux, obtained from two different models (EVACROP and APSIM), affect NO3 -N leaching loads. The effect of interpolation of NO3 -N concentrations based on days or drainage was also addressed. The models were set up according to a 2-yr field experiment with spring barley (Hordeum vulgare L. Quinch) with different levels of N fertilization rates on a loamy soil at Flakkebjerg, Denmark. Due to small differences in measured NO3 -N concentrations between sequential samplings, the method of interpolation did not significantly affect NO3 -N leaching in the two periods investigated. Although there is no standard against which leaching losses from different approaches can be tested, results highlight that the modeling of water uptake as affected by N supply influences the amount of drainage and thus calculated NO3 -N leaching. Therefore, for experiments with varying N fertilization levels, the APSIM model, which accounts for N nutrition on crop water use, is likely more accurate. For common fertilization rates, the simpler EVACROP seems appropriate. Thus, when using suction cup data for testing models or for evaluating mitigation options for nitrate leaching, the use of an appropriate model for estimating water fluxes is important.


Assuntos
Fertilizantes/análise , Nitratos/análise , Agricultura , Solo , Sucção
14.
J Environ Qual ; 49(4): 1054-1061, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33016482

RESUMO

Cadmium (Cd) can accumulate in soil from the application of phosphorus fertilizer. However, there is little information on what happens to soil Cd concentrations when Cd inputs stop. This study used soil and pasture samples collected from a long-term field trial to measure changes in Cd concentrations in soil for 22 yr after Cd inputs from fertilizer had stopped and assessed whether the application of nitrogen (N) (50 kg ha-1  yr-1 ) could increase plant uptake of Cd and reduce soil Cd concentrations. It was found that there was no significant change in total or labile soil Cd (1 M CaCl2 extractable) concentrations after Cd inputs stopped. The application of N did not significantly (P < .05) increase dry matter yield or increase Cd solubility. As a result, N did not enhance plant uptake of Cd. A mass balance that included Cd loss via plant uptake and Cd leaching confirmed they were insufficient to result in a detectable decrease in soil Cd concentration over the 22-yr interval of the trial. It appears that even an acid soil with low amounts of carbon (2.67%), iron/aluminum oxides, and clay can still strongly retain Cd, preventing Cd depletion from the soil, despite stopping Cd inputs and trying to enhance plant uptake of Cd from the application of N fertilizer.


Assuntos
Fertilizantes/análise , Poluentes do Solo/análise , Cádmio/análise , Fósforo , Solo
15.
Chemosphere ; 261: 128018, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113642

RESUMO

Highly persistent, toxic and bioaccumulative per - and polyfluoroalkyl substances (PFAS) represents a serious problem for the environment and their concentrations and fate remain largely unknown. The present study consists of a PFAS screening in sludges originating from 43 wastewater treatment plants (WWTPs) in the Czech Republic. To analyze an extended group of PFAS consisting of 32 PFAS, including GenX and other new replacements of older and restricted PFAS in sludge, a new method was optimized and validated using pressurized solvent extraction, followed by the SPE clean-up step to eliminate the observed matrix effects and LC-MS/MS. The results revealed high PFAS contamination of sewage sludge, reaching values from 5.6 to 963.2 ng g-1. The results showed that in the majority of the samples (about 60%), PFOS was the most abundant among the targeted PFAS, reaching 932.9 ng g-1. Approximately 20% of the analyzed samples contained more short-chain PFAS, suggesting the replacement of long-chain PFAS (especially restricted PFOA and PFOS). GenX was detected in 9 samples, confirming the trend in the use of new PFAS. The results revealed that significantly higher contamination was detected in the samples from large WWTPs (population equivalent > 50,000; p-value <0.05). Concerning the application of sludge in agriculture, our prediction using the respective PFAS bioconcentration factors, the observed concentrations, and the legislatively permitted management of biosolids in Czech Republic agriculture revealed that PFAS can cause serious contamination of cereals and vegetables (oat, celery shoots and lettuce leaves), as well as general secondary contamination of the environment.


Assuntos
Ácidos Alcanossulfônicos/análise , Fluorcarbonetos/análise , Contaminação de Alimentos/análise , Propionatos/análise , Esgotos/química , Poluentes do Solo/análise , Verduras/química , Ácidos Alcanossulfônicos/metabolismo , Bioacumulação , Biossólidos , Cromatografia Líquida , República Tcheca , Fertilizantes/análise , Fluorcarbonetos/metabolismo , Propionatos/metabolismo , Poluentes do Solo/metabolismo , Espectrometria de Massas em Tandem , Verduras/crescimento & desenvolvimento , Verduras/metabolismo , Águas Residuárias/química , Purificação da Água
16.
Chemosphere ; 261: 128122, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113643

RESUMO

Heavy metals in soil are harmful to human health via the food chain, but little is known about the mechanism of reducing bioavailability of Cd or Pb to maize (Zea mays L.) by applying complex amendments to soil. A field experiment was conducted at a tropical site in Hainan Province, China, that had been subjected to soil pollution by Cd and Pb from past mining activities. There were ten treatment groups comprising a mixture of biochar, hydroxyapatite (HAP), manure, and plant ash in varying proportions and at three different rates. Compared with untreated soil, all treatments increased pH by 2-3 units in bulk soil or 1-2 units in rhizosphere soil. For all amendments, the concentration of Cd in all parts of maize plants was decreased compared with unamended soil, but this effect was much smaller for Pb. The greatest effect was found with a mixture containing the ratio of HAP:manure:biochar:plant ash as 6:4:2:1 when applied at 20.1 t ha-1. The dominant microbial group in contaminated soil was Proteobacteria. There is evidence that this group can immobilize Cd by mechanisms that include biosorption and bioprecipitation. It was concluded that the mixed amendments containing biochar, HAP, manure, and plant ash can be useful in decreasing Cd uptake by maize. The amendment in this study likely operates through a combination of soil chemical changes and by influencing the soil-microbe-plant interaction.


Assuntos
Fertilizantes/análise , Metais Pesados/análise , Poluentes do Solo/análise , Zea mays/química , Disponibilidade Biológica , Carvão Vegetal/química , China , Durapatita/química , Humanos , Esterco/análise , Mineração , Modelos Teóricos , Rizosfera , Solo/química , Zea mays/metabolismo
17.
Sci Total Environ ; 741: 140488, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32887004

RESUMO

Nitrogen fertilization significantly increases greenhouse gases (GHGs) emission, when applied from inorganic or organic sources. Minimizing GHGs from agroecosystems without compromising crop yield for stabilization of green production systems remains a challenge. Being an integral component of wheat production technology, the nitrogen (N) application deems to be indispensable. Thus, to reduce the application of N fertilizer and keep in view the minimization of GHGs emission, without compromising soil fertility and wheat production, field experiments were performed with treatments included maize straw mulch (S1: 0, S2: 4500, S3: 9000 kg ha-1) and nitrogen fertilizer (N1: 0, N2: 192 and N3: 240 kg ha-1) during 2015-17. Results showed that the cumulative CO2 and N2O emission from 9000 kg ha-1 of maize straw mulch with 192 kg N ha-1 (S3N2) significantly decreased by 0.67% and 33.7%, respectively, averaged over two years compared with that of 9000 kg ha-1 of maize straw mulch with 240 kg N ha-1 (S3N3). Likewise, the average soil moisture content significantly increased by 10% and 10.6% for S3N2 and S3N3 treatments at 0-10 cm soil depth, respectively, compared to S1N1. Similarly, the S3N2 and S3N3 treatments had lowered the soil temperature by 0.2 and 0.1 °C, respectively, over S1N1 in wheat grown fields. The grain yield of wheat was increased by 45% and 45% under S3N3 and S3N2 treatments than S1N1, respectively. The S3N2 treatment was more economical than S3N3 for wheat crop. Therefore, maize straw mulch (S3) combined with 20% less N fertilizer (N2) from commercial source were considered as a viable production technology to improve crop yield, and reduce soil CO2 and N2O emissions.


Assuntos
Fertilizantes/análise , Triticum , Agricultura , Dióxido de Carbono , China , Nitrogênio/análise , Óxido Nitroso/análise , Solo , Zea mays
18.
PLoS One ; 15(9): e0238469, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877469

RESUMO

The spatial arrangement and pore size distribution play an important role in accumulation and protection of exogenous organic matter (EOM) in the soil, but how different organic materials contribute to modify pore structure is poorly understood. We aimed at exploring possible changes in the complexity of the soil phase during fertilization with different doses of digestate and sludges sourced from the agro-food industry. For this purpose, the short-term effects-one year, of soil fertilization, were investigated in several sampling periods and within two depths (0-25 cm and 25-40 cm). Changes in the specific surface area (SSA), total pore volume (VMIP), total pore area (SMIP), average pore radius (RMIP) and pore size distribution (PSD) were monitored using N2 adsorption/desorption (NAD) and mercury porosimetry (MIP) methods. Our results showed that the intensity of observed changes depended on the type and dose of organic material, soil depth and sampling date. Accumulation of EOM increased with soil depth, masking a large proportion of SSA. Deeper soil layer was more susceptible to changes in the pore size distributions due to the formation of new elongated pores. We concluded that this specific structural porosity was related to the decomposition of organic matter during the formation of soil aggregates.


Assuntos
Agricultura/métodos , Fertilizantes/análise , Solo/química , Adsorção , Indústria Alimentícia , Mercúrio/química , Nitrogênio/química , Porosidade , Esgotos/química
19.
PLoS One ; 15(9): e0239552, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970779

RESUMO

Low productivity and climate change require climate-smart agriculture (CSA) for sub-Saharan Africa (SSA), through (i) sustainably increasing crop productivity, (ii) enhancing the resilience of agricultural systems, and (iii) offsetting greenhouse gas emissions. We conducted a meta-analysis on experimental data to evaluate the contributions of combining organic and mineral nitrogen (N) applications to the three pillars of CSA for maize (Zea mays). Linear mixed effect modeling was carried out for; (i) grain productivity and agronomic efficiency of N (AE) inputs, (ii) inter-seasonal yield variability, and (iii) changes in soil organic carbon (SOC) content, while accounting for the quality of organic amendments and total N rates. Results showed that combined application of mineral and organic fertilizers leads to greater responses in productivity and AE as compared to sole applications when more than 100 kg N ha-1 is used with high-quality organic matter. For yield variability and SOC, no significant interactions were found when combining mineral and organic fertilizers. The variability of maize yields in soils amended with high-quality organic matter, except manure, was equal or smaller than for sole mineral fertilizer. Increases of SOC were only significant for organic inputs, and more pronounced for high-quality resources. For example, at a total N rate of 150 kg N ha-1 season-1, combining mineral fertilizer with the highest quality organic resources (50:50) increased AE by 20% and reduced SOC losses by 18% over 7 growing seasons as compared to sole mineral fertilizer. We conclude that combining organic and mineral N fertilizers can have significant positive effects on productivity and AE, but only improves the other two CSA pillars yield variability and SOC depending on organic resource input and quality. The findings of our meta-analysis help to tailor a climate smart integrated soil fertility management in SSA.


Assuntos
Agricultura/métodos , Fertilizantes/análise , Solo/química , África ao Sul do Saara , Carbono/análise , Sequestro de Carbono/fisiologia , Esterco/análise , Minerais , Nitrogênio/análise , Fósforo , Triticum , Zea mays/metabolismo
20.
J Environ Manage ; 276: 111211, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32987233

RESUMO

Fertilizers have become an essential part of our global food supply chain and are necessary to sustain our growing population. However, fertilizers can also contribute to greenhouse gas (GHG) emissions, along with other potential nutrient losses in the environment, e.g. through leaching. To reduce this environmental impact, tools such as life cycle assessments and decision support systems are being used to aid in selecting sustainable fertilization scenarios. These scenarios often include organic waste-derived amendments, such as manures, composts and digestates. To produce an accurate assessment and comparison of potential fertilization scenarios, these tools require emission factors (EFs) that are used to estimate GHG emissions and that are an integral part of these analyses. However, such EFs seem to be very variable in nature, thereby often resulting in high uncertainty on the outcomes of the analyses. This review aims to identify ranges and sources of variability in EFs to provide a better understanding of the potential uncertainty on the outcomes, as well as to provide recommendations for selecting EFs for future studies. As such, an extensive review of the literature on GHG emissions from production, storage, transportation and application of synthetic fertilizers (N, P, K), composts, digestates and manures was performed. This paper highlights the high variability that is present in emissions data and confirms the great impact of this uncertainty on the quality and validity of GHG predictions related to fertilizers. Variability in EFs stem from the energy source used for production, operating conditions, storage systems, crop and soil type, soil nutrient content, amount and method of fertilizer application, soil bacterial community, irrigation method, among others. Furthermore, a knowledge gap exists related to EFs for potassium fertilizers and waste valorization (anaerobic digestion/composting) processes. Overall, based on this review, it is recommended to determine EFs on a case by case basis when possible and to use uncertainty analyses as a tool to better understand the impact of EF variability.


Assuntos
Fertilizantes , Gases de Efeito Estufa , Agricultura , Fertilizantes/análise , Esterco/análise , Nitrogênio/análise , Solo
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